1. Field of the Invention
The present invention relates to a photosensitive composition that is used in the production step of semiconductors such as IC, the production of circuit boards of liquid crystals, thermal heads, etc., and other photo-fabrication steps and for lithographic printing plates, acid curable compositions, radical curable compositions, etc.
2. Description of Related Art
Photosensitive compositions are a composition that generates an acid or radical by external stimulations such as actinic rays and changes physical properties of a site to be stimulated by its reaction. More preferably, photosensitive compositions are a pattern forming material that changes dissolution of irradiated areas and non-irradiated areas by actinic rays in a developer to form a pattern on a substrate.
As such photosensitive compositions are enumerated chemical amplification resist compositions containing an acid generator capable of generating an acid upon irradiation with actinic rays.
With respect to such chemical amplification resist compositions, JP-A-2002-116546 discloses a composition containing a mixed acid generator of an oxoalkylsulfonium salt having no substituent in a methylene moiety and a triarylsulfonium salt or a diphenyliodonium salt; JP-A-2001-187780 and EP-1113334 disclose oxoalkyl group-containing sulfonium salts; and JP-A-10-133371 and JP-A-10-73919 disclose 2-oxo cyclic alkyl group-containing sulfonium salts. However, though these oxoalkylsulfonium salts have high transparency against rays of not longer than 220 nm, they have a low ability to generate an acid. Therefore, there was involved a problem such that sensitivity is lowered.